Flight history · Aug 2025 – Jul 2026 · US DOT on-time records
WN 3891 · St Louis (STL) → Boston (BOS)
Sold by Southwest. Still flying: 48 of the last 56 days (Mon, Tue, Wed, Thu, Fri, Sun).
Arrives on time82%within 15 minutes, of 50 flights
Cancelled0.0%of scheduled flights
An hour or more late4%of flights that operated
When late, on average52 minlate, among flights 15+ min late
Schedule
Typical times in the Jun 6 – Jul 31, 2026 schedule, local at each airport (Boston is 1 h ahead of St Louis).
- Leaves STL
- 10:05
- Arrives BOS
- 13:40
- Flight time
- 2h 35m
- Days flown, last 8 weeks
- 48 of 56
Each square is a day, Sat Jun 6 to Fri Jul 31, two weeks per row (each column is the same weekday); filled = flew.
How late it arrives
Share of flights that operated arriving more than this late.
Horizontal: minutes late at arrival (0 to 3 hours). Vertical: share of flights later than that.
Its hour at STL
All flights leaving St Louis (STL) at 10–11 am, wherever they’re going: 85% left within 15 minutes and 0.6% were cancelled (5,330 flights in the year). Other Southwest flights on this route →
Upcoming forecasts
Our odds that this flight is late or cancelled on the days we publish.